Intelligent Power Today Magazine

While the threat of shock and electrocution from inadvertent contact with energized parts has long been recognized, the arc flash and arc blast hazards have only fairly recently been incorporated into the electrical safety standards.

The U.S. federal agency the Occupational Safety and Health Administration (OSHA) enforces electrical workplace safety standards outlined in the National Fire Protection Association’s NFPA 70E: “Standard for Electrical Safety in the Workplace”. Basic compliance with guidelines in the NFPA 70E 2015 Edition, can be established with a five-step process.

Absence of voltage testing is a vital step in the process of verifying and establishing a de-energized state of any electrical system. As detailed in NFPA 70E clause 4.2.5., there is a specific and approved approach to establishing an electrical safe work condition with the following steps:

• determine all possible source of electrical supply
• interrupt the load current, open the disconnecting device for each possible source
• verify where possible that all blades of the disconnecting devices are open
• release or block any stored energy
• apply lockout device in accordance with documented and established work procedures
• using an adequately rated portable...